From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: * X-Spam-Status: No, score=1.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,URIBL_DBL_ABUSE_MALW autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 292DBC33CB2 for ; Wed, 29 Jan 2020 10:37:02 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AA00120708 for ; Wed, 29 Jan 2020 10:37:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="HfKXVxgU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA00120708 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Io9lvXcCvRD2Ct3vPLTkqbAefKsLgAgkcm9kc/UpiVY=; b=HfKXVxgUyIY2z4 5Td7cdDWwmwpQQKEhD6KI2of5VMKJVLl/eTwtfhqNAOg/PyC5CXoQlZmuDNpWVzYpmWkJA2GUEQ6T 5AmJPvoyplV7heobU+t7JuuJHBzSqmDXVGahFvYPlSdJvC75ldLQKHDLhe/YLvze88s2wKPFaKHj/ xwUKVzmKaZWqrTa+0lTLcfanHjKRRiKK7N2lFHKN+kjAcVvugdh6SYs9WaOcw3f7sMyXh23YwWpEN Z8GdHPf9dRaJ2ELAv07mFfnVdRujHeVbeVFiSo97SchBWpUZ8Fe/nLBzbh/vc88mdSld48MV5fMuQ ME2OUJMInMMr9lZxiv9g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iwkiO-0006TW-1E; Wed, 29 Jan 2020 10:36:56 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iwkiJ-0006SZ-JM; Wed, 29 Jan 2020 10:36:53 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F35521FB; Wed, 29 Jan 2020 02:36:47 -0800 (PST) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.47]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B1FB23F52E; Wed, 29 Jan 2020 02:36:42 -0800 (PST) Date: Wed, 29 Jan 2020 10:36:40 +0000 From: Catalin Marinas To: Qian Cai Subject: Re: [PATCH V12] mm/debug: Add tests validating architecture page table helpers Message-ID: <20200129103640.GA668562@arrakis.emea.arm.com> References: <20200128174709.GK655507@arrakis.emea.arm.com> <69091BA4-18C4-4425-A5E2-31FBE4654AF9@lca.pw> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <69091BA4-18C4-4425-A5E2-31FBE4654AF9@lca.pw> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200129_023651_725960_6E1AAABE X-CRM114-Status: GOOD ( 15.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , James Hogan , Heiko Carstens , Michal Hocko , linux-mm@kvack.org, Paul Mackerras , sparclinux@vger.kernel.org, Ingo Molnar , linux-s390@vger.kernel.org, Jason Gunthorpe , Michael Ellerman , x86@kernel.org, Russell King - ARM Linux , Matthew Wilcox , Steven Price , Tetsuo Handa , Vlastimil Babka , linux-snps-arc@lists.infradead.org, Kees Cook , Anshuman Khandual , Gerald Schaefer , Mark Brown , "Kirill A . Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, Christophe Leroy , Sri Krishna chowdary , Masahiro Yamada , Greg Kroah-Hartman , Ard Biesheuvel , Dave Hansen , linux-mips@vger.kernel.org, Ralf Baechle , linux-kernel@vger.kernel.org, Paul Burton , Mike Rapoport , Thomas Gleixner , Vineet Gupta , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jan 28, 2020 at 02:07:10PM -0500, Qian Cai wrote: > On Jan 28, 2020, at 12:47 PM, Catalin Marinas wrote: > > The primary goal here is not finding regressions but having clearly > > defined semantics of the page table accessors across architectures. x86 > > and arm64 are a good starting point and other architectures will be > > enabled as they are aligned to the same semantics. > > This still does not answer the fundamental question. If this test is > simply inefficient to find bugs, Who said this is inefficient (other than you)? > who wants to spend time to use it regularly? Arch maintainers, mm maintainers introducing new macros or assuming certain new semantics of the existing macros. > If this is just one off test that may get running once in a few years > (when introducing a new arch), how does it justify the ongoing cost to > maintain it? You are really missing the point. It's not only for a new arch but changes to existing arch code. And if the arch code churn in this area is relatively small, I'd expect a similarly small cost of maintaining this test. If you only turn DEBUG_VM on once every few years, don't generalise this to the rest of the kernel developers (as others pointed out, this test is default y if DEBUG_VM). Anyway, I think that's a pointless discussion, so not going to reply further (unless you have technical content to add). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel